JP3139515B2 - Fiber sheet and circuit board using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber sheet and a circuit board using the same, and more particularly to a fiber sheet comprising a fibrous material having excellent dielectric properties and a resin composition containing polyphenylene sulfide as a main component. The present invention relates to a circuit board using the fiber sheet as a base material.

[0002]

2. Description of the Related Art In the field of electric and electronic components, there is an increasing demand for insulating base materials having excellent heat resistance and high frequency characteristics from the viewpoint of miniaturization and high performance of equipment. Among them, in order to cope with the information age, circuit boards are strongly demanded for high-speed signal processing and high-frequency support, and it is strongly desired that they have excellent high-frequency characteristics.

As a substrate in this field, a substrate in which glass cloth is impregnated with an epoxy resin (hereinafter sometimes abbreviated as glass epoxy), a polyimide film, a fluorine-based film, and a substrate in which glass cloth is impregnated with a fluorine-based resin. and so on. Further, poly-p-phenylene sulfide (hereinafter, PPS)
May be abbreviated. The unstretched sheet and the biaxially oriented film of (2) have recently received particular attention. In addition, biaxially oriented poly-p-phenylene sulfide film (hereinafter referred to as PPS)
Sometimes abbreviated as film. Examples of the laminated film or laminate using (1) are those obtained by laminating an aromatic polyamide fiber sheet with an adhesive (JP-A-60-63).
158), (2) a laminate of PPS with a fibrous material (JP-A-63-237949), and (3) a laminate film with a fluorine-based film for the purpose of improving the impact resistance of the PPS film. (JP-A-62-292432),
(4) A laminate with a fibrous material that is infusible at a temperature of 300 ° C. and has a coefficient of thermal expansion at a temperature of 150 ° C. of 50 × 10 ⁻⁶ ° C.- ¹ or less (Japanese Patent Application Laid-Open No. 60-63158) ), Etc. are known.

[0004]

However, each of the above-mentioned films, laminated films and laminates has the following problems. The glass epoxy is inferior in high-frequency characteristics, and has a problem in moisture absorption characteristics. Therefore, there is a problem that as the frequency increases, the dielectric characteristics further deteriorate. Polyimide films have high heat resistance, but are inferior in high frequency characteristics and moisture absorption characteristics. In addition, the base material obtained by impregnating a fluorine-based film or glass cloth with a fluorine resin has poor adhesiveness, and there is a problem that it is difficult to print or paste when plating a circuit or forming a metal foil or through-hole processing. .

On the other hand, an unstretched sheet of PPS satisfies properties such as thermal dimensional stability, low moisture absorption, flame retardancy, and high-frequency characteristics, but has a lower heat resistance temperature (glass transition) than a biaxially oriented film. If the temperature exceeds the point, thermal deformation is apt to occur.), And as the number of processing steps increases, crystallization proceeds and the material becomes brittle. When used as a printed circuit board, the crystal size and the like are controlled to satisfy the heat resistance and brittleness, but there is a problem that heat deformation easily occurs when heat is applied suddenly as in soldering. .

In addition, since the PPS film undergoes a dimensional change due to heat shrinkage, for example, when heat is applied in the process of manufacturing a circuit board, the circuit is likely to shift. Although a process for reducing the heat shrinkage rate is performed by an annealing process or the like, if the heat shrinkage rate at 250 ° C. is set to 1% or less, the flatness of the film is significantly deteriorated. There is also a problem that the laminated circuit board is easily torn during the processing of through holes.

[0007] In the case of laminating the aromatic polyamide fiber sheet of the above item (1) with an adhesive, the heat resistance is improved, but the heat resistance of the adhesive adversely affects the substrate (that is, The heat resistance of the adhesive governs the heat resistance of the entire substrate.), And the excellent properties of PPS cannot be utilized. In addition, the conductive paste may seep during through-hole processing,
The plating is difficult to ride, and the through-hole processing cannot be performed.

The laminate with the PPS fibrous material of the above item (2) has improved mechanical properties, but does not improve heat resistance and thermal dimensional change.

The laminated film with the fluorine-based film of the above item (3) has excellent dielectric properties and improved mechanical properties, but it is difficult to mount conductive paste or plating at the time of through-holes, and there is a problem in workability of through-holes. .

[0010] The laminate of the above item (4) comprises a fibrous material and PP.
The adhesive strength to the S film is weak, and it is easily peeled off when a force such as bending is applied. In addition, there is a problem in workability of through holes.

Although it is conceivable to impregnate the PPS resin with a fibrous material such as glass cloth, there is a problem in that the excellent dielectric properties and moisture absorption properties, which are the features of PPS, are reduced.

[0012]

SUMMARY OF THE INVENTION The present invention makes use of the excellent high-frequency characteristics, low moisture absorption, and flame retardancy of PPS, is excellent in heat resistance and processability as a circuit board, and achieves high-speed signal processing and high-frequency processing. Insulating base material suitable for circuit boards that require
And a circuit board using the same (including a multilayer circuit board)
The purpose is to provide.

[0013]

Fiber sheet of SUMMARY OF THE INVENTION The present invention along this purpose, the dielectric constant is 5.0 at the frequency of 1 MHz or less, the dielectric loss is 0.02 or less polytetra
A fibrous sheet fibrous composed mainly of fluoroethylene resin (A) to <br/> polyphenylene sulfide resin composition as a main component (B) is formed by impregnation, 250 ° C.
Has a heat shrinkage of 1.0% or less. By providing an electric circuit on at least one surface of the fiber sheet, the circuit board of the present invention is manufactured.

The fibrous material (A) according to the present invention is a thin body composed of an aggregate of fibers,
Non-woven fabric, cloth, felt, paper, etc.
0 μm (preferably 10 to 300 μm).
Further, the dielectric constant and the dielectric loss of the fibrous composition at a frequency of 1 MHz are 5.0 or less and 0.0, respectively.
2 or less (preferably, the dielectric constant is 4.0 or less, and the dielectric loss is 0.01 or less). When the dielectric constant and the dielectric loss exceed the above values, not only the excellent dielectric properties of PPS are lowered, but also it becomes impossible to cope with a high-speed signal processing and high-frequency compatible substrate. Further, the melting point or softening point of the fibrous material is preferably 270 ° C. or more. The base material of the fibrous material is mainly fluororesin.
In particular, in the present invention, polytetrafluoroe
The fibrous material (A) is mainly composed of a tylene resin. Here, the relationship between the electric flux density (D) and the electric field (E) is represented by D = εE, and the dielectric constant is ε at that time. The dielectric loss refers to a phenomenon or loss of energy as heat when an AC electric field is applied to a dielectric. Further, the fibrous material may be processed such as processing such as easy adhesion and coloring.

[0015] In particular, fibrous material used in the present invention Poriteto
Frequency characteristic torque loss of <br/> a resin composition mainly comprising La fluoroethylene resin is an object of the present invention, a low hygroscopicity, to over balance and workability properties such as heat resistance Preferred . The mainly comprising polytetrafluoroethylene resin in here, more than 50% by weight of the resin composition is poly
Polyethylene means tetrafluoroethylene resin
When the content of the tetrafluoroethylene resin is 50% by weight or less, high frequency characteristics, moisture absorption characteristics, and the like are deteriorated. Other polymers and inorganic additives may be contained as long as the remaining amount is 50% by weight or less. It may be mixed with other fibers and laminated.

In the present invention, poly-p-phenylene sulfide (hereinafter sometimes abbreviated as PPS) is
70 mol% or more (preferably 80 mol%) of the repeating unit
Above) refers to a polymer comprising the structural unit represented by Structural Formula 1. If the content of such a component is less than 80 mol%, the crystallinity of the polymer, the heat transition temperature, and the like are low, and the heat resistance, dimensional stability, mechanical properties, and the like, which are features of the resin composition containing PPS as a main component, are impaired.

[0017]

Embedded image

In the above PPS, the repeating unit 30
If it is less than mol%, preferably less than 20 mol%, a unit containing a copolymerizable sulfide bond may be contained. The method of copolymerizing the polymer may be random or block type.

In the present invention, a resin composition containing poly-p-phenylene sulfide as a main component (hereinafter sometimes abbreviated as PPS composition) refers to a composition containing 60% by weight or more of poly-p-phenylene sulfide. Say. PPS
If the content is less than 60% by weight, the mechanical properties, heat resistance, dielectric properties and the like of the fiber sheet made of the composition are impaired. The remaining less than 40% by weight of the composition may contain additives other than PPS, such as polymers, inorganic or organic fillers, lubricants, and coloring agents. Further, the melt viscosity of the PPS composition is 100 to 50,000 poise (more preferably, 5 to 50000 poise) at a temperature of 300 ° C. and a shear rate of 200 sec ^−1.
The range of (0000 to 20000 poise) is preferable in view of the workability of lamination.

[0020] The fibrous sheet of the present invention, all SANYO consisting fibrous material described above (A) and PPS of resin composition (B), in particular, to facilitate achieving the object of the present invention
To, it shall der have been impregnated B to part or all of A
You. Here, the impregnation refers to a state in which the resin enters around the elementary fibers constituting the fibrous material and is adhered and solidified to the elementary fibers. The impregnation state can be measured, for example, by the degree of ink penetration. It is particularly preferred that the fiber sheet of the present invention has an ink penetration of 5.0 or less (more preferably 3.0 or less) as described below. When the degree of permeation exceeds 5.0, the dielectric properties deteriorate due to the influence of moisture and the like, and the workability of the through hole becomes difficult, and the object of the present invention is hardly achieved. Here, the degree of ink penetration is
When " Magic Ink " (registered trademark) is soaked for 1 minute on the surface in the cross-sectional direction (thickness direction) of the fiber sheet, the ink penetrates into the inside. Is the length (mm) measured from the surface of the fiber sheet, and is a parameter indicating the degree of impregnation of the fiber sheet.

The ratio of the (A) layer to the (B) layer of the fiber sheet is not particularly limited, but when the thickness of each layer is measured from a cross section of the fiber sheet by a microscope or the like, the (B) layer of a single layer is obtained. The surface roughness is such that the ratio (b / a) of the thickness (b) to the thickness (a) of the fibrous material layer impregnated with PPS is 0.1 to 3 (more preferably 0.25 to 2.5). It is preferable from the viewpoints of (processability of circuit formation), impregnation, dielectric properties, heat resistance, and thermal dimensional stability. Further, the layer (a) of the fiber sheet of the present invention does not necessarily need to be located at the center in the thickness direction of the fiber sheet, and may be located at a shifted position. Further, the above-described configuration may be formed by superposing two or more layers.

Further, the fiber sheet of the present invention must have a heat shrinkage at 250 ° C. of 1.0% or less. If the heat shrinkage exceeds 1.0%, the circuit is likely to be misaligned during the manufacture of the circuit board, and in the case of a multilayer circuit board, the position of the through hole is likely to be misaligned. In addition, deformation or warpage occurs during soldering. Here, the heat shrinkage ratio is a value obtained by dividing a dimensional change when aged at a temperature of 250 ° C. for 30 minutes by a sample length before aging and expressing the percentage as a percentage.
Further, a treatment such as annealing (relax) may be performed on the fiber sheet for the purpose of suppressing the heat shrinkage.

The dielectric constant and dielectric loss at 1 MHz of the fiber sheet of the present invention are 3.5 or less and 0.00, respectively.
5 or less, and the moisture absorption rate is 0.1 or less (25 ° C., 75% R
H, 72 hours) is preferable for achieving the object of the present invention. The thickness of the entire fiber sheet is 20 to 15
00 μm (more preferably 20 to 1000 μm, and still more preferably 20 to 700 μm).

The fiber sheet of the present invention is particularly suitable for a base substrate of a circuit board (including a multilayer circuit board). The circuit board of the present invention is obtained by forming an electric circuit on at least one surface of the fiber sheet. An electric circuit is a passage of electricity in which a conductor is patterned.
Metals such as copper, aluminum and iron, or conductive paints containing copper, silver, carbon and the like are usually used. Further, electric or electronic components may be mounted on the electric circuit. Further, two or more circuit boards may be laminated.

Next, a method for producing a fiber sheet and a circuit board of the present invention will be described, but the present invention is not limited to this method. First, a fibrous material used in the present invention, Poriteto
A fiber mainly composed of a lafluoroethylene resin is formed into a cloth by a known method such as plain weaving, twill weaving, or entangled weaving. When a non-woven fabric is used, the resin composition or its fiber can be obtained by a known method such as a wet method, a dry method, and a spun bond. Further, a treatment such as a calendar treatment may be performed to entangle the fibers.

The PPS used in the present invention is obtained by reacting an alkyl sulfide with a paradihalobenzene in a polar solvent at high temperature and high pressure. In particular, it is preferable to react sodium sulfide with paradichlorobenzene in an amide high-boiling-point polar solvent such as N-methylpyridone. In this case, in order to adjust the degree of polymerization, so-called polymerization aids such as caustic alkali and alkali metal carboxylate are added, and
The reaction is preferably performed at 0 ° C. The polymerization system pressure and polymerization time are appropriately determined depending on the type and amount of the auxiliary agent used, the desired degree of polymerization, and the like. The obtained granular or powdery polymer is washed with water or / and a solvent to separate by-product salt, a polymerization aid, unreacted monomers and the like.

Various methods can be used for impregnating the polymer with a fibrous material and laminating it. The following three typical methods can be exemplified. (1) A method of producing a fiber sheet by thermocompression bonding a PPS sheet obtained by molding the above polymer into an unstretched and unoriented sheet to a fibrous material. In producing by this method, first, a method for producing an unstretched sheet of PPS will be described. The above PPS is supplied to a melt extruder represented by an extruder, heated to a temperature not lower than the melting point of the polymer (more preferably in the range of 300 to 350 ° C.) and sufficiently kneaded, and then continuously fed from a slit die. And rapidly cooled to a temperature below the glass transition point of the PPS to obtain a substantially non-oriented PPS sheet. Next, the PPS sheet and the fibrous material are overlapped,
Thermocompression bonding is performed at a temperature of 40 ° C. or more (preferably 260 ° C. or more) under a pressure of 1 to 30 kg / cm ² by a heated roll press or a hot plate press. Further, the fiber sheet is cooled via a cooling roll, a cooling plate, fresh air, water or the like for the purpose of maintaining the flatness of the fiber sheet. The thermocompression bonding temperature is 240 ° C
In the following, the impregnating property is poor, and the dielectric properties, the workability of the through hole, and the like are reduced. The pressure during thermocompression bonding is 1kg / cm
^If it is less than ² , the impregnating property is poor, and if it exceeds 30 kg / cm ² , the flatness of the fiber sheet tends to deteriorate. When the fibrous material and the PPS sheet are thermocompressed, the fibrous material
In the case of two layers of PS sheet, PPS sheet, fibrous material,
In some cases, the three layers of the PPS sheet are superposed in this order, and the latter is preferred from the viewpoint of impregnation. The thickness ratio (B / A) of the fibrous material (A) and the PPS sheet (B) before thermocompression bonding is preferably in the range of 0.2 to 5.0 in order to achieve the object of the present invention .

(2) A method in which PPS is extruded from a slit-shaped die and pressure-bonded while being laminated on a lower fibrous material, or thereafter, is laminated by thermocompression bonding. The conditions for thermocompression bonding in this method are the same as in the method (1).

(3) A method of producing a fiber sheet by thermocompression bonding a biaxially oriented PPS film to a fibrous material. In producing by this method, first, a method for producing a biaxially oriented PPS film will be described. PP obtained by the method of (1)
The S sheet is biaxially stretched by a known method. For example, when a sequential biaxial stretching method is used, stretching conditions are a stretching temperature of 90 to 120 ° C. and a stretching ratio of 2.0 in both the longitudinal direction and the width direction.
A range of -4.5 times is preferred. Subsequently, heat treatment is performed as necessary. As a heat treatment method, a tenter method is used. The heat treatment is usually carried out in a temperature range of 200 to 290 ° C. under a fixed length or a limited shrinkage of 15% or less. Further, both directions may be relaxed to improve the thermal dimensional stability of the film. The thus-obtained biaxially oriented PPS film and the fibrous material are superimposed, and heated at a temperature equal to or higher than the melting point of PPS (preferably 285 to 350 ° C.) and a pressure of 1 to 30 kg / cm ^2. Thermocompression bonding is performed by a roll press or hot plate press. Further, the fiber sheet is cooled via a cooling roll, a cooling plate, fresh air, water or the like for the purpose of maintaining the flatness of the fiber sheet. The above thermocompression bonding temperature is PP
If the melting point is less than the melting point of S, the impregnating property is poor, and the dielectric properties, the workability of through holes, and the like are reduced. The pressure during thermocompression bonding is 1k
If it is less than g / cm ² , the impregnation is poor, and conversely, 30 kg / c
If it exceeds m ² , the flatness of the fiber sheet tends to deteriorate. When the fibrous material and the PPS sheet are thermocompression-bonded, two layers of the fibrous material and the PPS sheet, and three layers of the PPS sheet, the fibrous material, and the PPS sheet may be overlapped in this order. The latter is preferred from the viewpoint of impregnation.
In addition, the fibrous material (A) and the PPS sheet (B) before thermocompression bonding
Is preferably in the range of 0.2 to 5.0 in order to achieve the object of the present invention .

Also, powdery, granular or pelletized PP
The S polymer is brought into direct contact with the fibrous material, and
Lamination can be performed under the condition (3). Furthermore, even if the fibrous material is impregnated with the PPS-based resin composition by the method described above or another method, the resin-impregnated material is polished or etched by a physical or chemical method.
It does not matter if the final product satisfies the constitution of the present invention and achieves the object.

Next, a method for manufacturing a circuit board based on the fiber sheet of the present invention will be described. A metal foil such as aluminum or copper is laminated on one or both sides of the fiber sheet by thermocompression bonding or an adhesive, or the above metal is laminated with a metal layer by a method such as a vacuum evaporation method, a plating method, or a sputtering method. Then, a desired circuit pattern is formed by etching using a ferric chloride aqueous solution or the like. Further, a circuit pattern is formed by a method such as a silk printing method using a conductive paint containing silver, copper, carbon, or the like, and the paint is cured by heat or ultraviolet rays as necessary. Further, if necessary, the above circuit boards are laminated to form a multilayer circuit board,
Process through holes and mount electrical and electronic components.

[Evaluation Method of Characteristics] Next, an evaluation method of characteristics and evaluation criteria used in the description of the present invention will be described. (1) Heat resistance A 2 cm square sample was floated in a solder bath set at a temperature of 260 ° C. and evaluated according to the following criteria. ：: No change at all. Δ: Softening, deformation, peeling, and wrinkles are observed in part. ×: Deformation or peeling such as waving or bending on the entire surface, and the dimensional change rates of the respective layers are greatly different.

(2) Dielectric Characteristics Dielectric constant and dielectric loss were measured at a frequency of 1 MHz.
(Measured according to JIS-C-6481.)

(3) Circuit Displacement The circuit board was passed through a furnace (far-infrared ray system) set at a temperature of 240 ° C. for 5 seconds, and the circuit was deviated from the circuit not passing through the furnace.

(4) Printability of Circuit A circuit having a width of 200 μm (line width of 200 μm) is printed on a sample with a conductive paint by silk printing. After drying, the state of the circuit is observed with a microscope and evaluated according to the following criteria. did. : Almost no swelling of circuit width, no change in line width, and no distortion. Δ: The width of the circuit is swollen, the line width is changed, and a part of the distortion is observed. ×: There are many swelling of the circuit width, change of the line width, and distorted portions.

(5) Through-Hole Properties The through-hole portions of the through-hole processed samples were observed with a microscope, and the adhesion of the conductive paint was examined.

(6) Degree of Infiltration of Ink 3 “ Magic Ink ” (registered trademark) ( “ Magic ” ink portion) was applied to the surface of the fiber sheet in the sectional direction (thickness direction).
When contacted for seconds, the ink seeps into the interior. The permeated length (the longest distance that the ink reached from the position where the " magic ink " came into contact) was represented by the length (mm) measured from the surface of the sheet. The "magic ink" used was that of Pentel Co., Ltd. (oil of penterpene middle character N50).

(7) Measurement of Thickness of Impregnated Layer (a) of Fiber Sheet and Resin Single Layer (b) and Thickness Ratio (b / a) A cross-sectional photograph of the laminate was taken with an electron microscope, and the fibrous material layer and The layer in which the fiber sheet was impregnated with the resin was defined as (a) and the layer composed of only the resin was defined as (b), and the thickness of each layer was determined from the photograph.

(8) Thermal Shrinkage Rate A certain direction of the sample is set as a reference direction, and the sample is cut into 100 mm × 10 mm in each of the reference direction and the 90 ° direction of the reference direction, and the length in the longitudinal direction is accurately read with a microscope. xm
m). Next, after aging for 30 minutes in a furnace (hot air system) heated to a temperature of 250 ° C., the length is accurately measured (ymm). Calculate the heat shrinkage (%) in each direction by the following formula,
The values are shown in the direction of larger heat shrinkage. Heat shrinkage (%) = [(xy) / x] × 100

(9) Moisture Absorption A sample is vacuum-dried at a temperature of 100 ° C. for 10 hours and then weighed (Q mg). The sample is aged at 75% RH and humidity of 25 ° C. for 72 hours, and then weighed again (Rmg). The moisture absorption was determined by the following equation. Moisture absorption rate (%) = [(RQ) / Q] × 100

[0041]

Next, the present invention will be described in detail with reference to examples. Example 1 (1) Preparation of fibrous material Monofilament (80 μm diameter) of polytetrafluoroethylene (hereinafter sometimes abbreviated as PTFE) is plain woven and has a density of 42 (pieces / 25 mm) cross sheet (thickness 1).
50 μm). The composition of the cloth has a dielectric constant and a dielectric loss at 1 MHz of 1.5 and 6 × 1, respectively.
It was 0 ^-4 .

(2) Preparation of PPS Sheet A composition obtained by uniformly dispersing 0.2% by weight of a silica fine powder having an average particle diameter of 0.7 μm in PPS (manufactured by Toray Phillip Spetrolium Co., Ltd.) is a 40 mm diameter extract. The mixture was melted at 310 ° C. with a ruder and filtered through a filter having a 95% cut hole diameter of 10 μm using a metal wire mesh.
It was extruded from a T-die having a linear lip with a gap of 0.5 mm and a gap of 0.5 mm, and was cast on a metal drum whose surface temperature was kept at 25 ° C. to obtain a 50 μm-thick unstretched and unoriented sheet of PPS.

(3) Preparation of Fiber Sheet The above-mentioned PPS sheet / fibrous material / PPS sheet was superposed in this order, impregnated by a hot plate press method, and laminated. The pressing conditions were a temperature of 290 ° C. and a pressure of 20 kg / cm ² . The thickness of the obtained fiber sheet was 210 μm. This fiber sheet is referred to as fiber sheet-1.

Example 2 (1) Preparation of fibrous material A PTFE nonwoven fabric (H9703 manufactured by Hamakawa Paper Mills) having a thickness of 120 μm and a density of 0.67 g / cm ³ was prepared. The dielectric constant and dielectric loss at 1 MHz of the nonwoven fabric composition were 1.2 and 5 × 10 ⁻⁴ , respectively.

(2) Preparation of Fiber Sheet Under the conditions of Example 1, PPS was extruded and laminated on both surfaces of the fibrous material to obtain four types of fiber sheets having different thicknesses. Further, the fiber sheet was heat-pressed under the conditions of Example 1 to impregnate the fibrous material and the resin. The thickness of the obtained fiber sheet is 130 μm, 190 μm, 280 μm, 470 μm
And fiber sheets 2 to 5, respectively.

Reference Example 1 , Comparative Example 1 A glass cloth having a thickness of 60 μm (Arisawa Seisakusho, EPC0
50) was prepared, treated with a silane coupling agent, and then applied to the entire glass cloth using a dispersion containing PTFE having a particle size of about 5 μm. The application method is a wet method. The obtained cloth had a dielectric constant of 1 MHz and a dielectric loss of 2.8 and 0.0018, respectively. The cloth was impregnated on both sides with a 25 μm-thick PPS film (a biaxially oriented film “TORELINA” manufactured by Toray) and laminated. The laminating method was the same as that in Example 1, and the conditions were 300 ° C., 260 ° C., and a pressure of 20 kg / cm ² . The obtained fiber sheets are referred to as fiber sheets-6 and 7, respectively.

[0047] Comparative Example 2 Reference Example 1 conditions the glass cloth coated with disperser John silicone resin (1 MHz dielectric constant, respectively dielectric loss 3.5,0.55) in the same manner as in Reference Example 1 to A PPS film was impregnated and laminated. Lamination temperature is 300
° C. The obtained fiber sheet is referred to as fiber sheet-8.

Comparative Example 3 A PPS film (Toray Co., Ltd.)
50 μm of a biaxially-oriented film “TORELINA”) was laminated via an epoxy-based adhesive (“Chemit Epoxy” manufactured by TE5920 Toray). The method of applying the adhesive is a gravure roll method, and the thickness of the adhesive is 15 μm / one side and drying is 1
3 minutes at a temperature of 00 ° C. The lamination condition is 120
The pressing pressure was 3 kg / cm ² at a temperature of ° C. One more
It was thermally cured at a temperature of 50 ° C. for 2 hours (fiber sheet 9).

Comparative Example 4 A 50 μm-thick film of a tetrafluoroethylene-hexafluoropropylene copolymer (“TOYOFLON” Toray)
Was subjected to a plasma treatment in Ar gas, and a PPS film (25 μm) was laminated on both surfaces.
It was thermally fused at a temperature of 10 ° C. and a pressure of 10 kg / cm ² (laminate-1).

Comparative Example 5 Under the conditions of Example 1, a PPS sheet having a thickness of 100 μm was obtained. The sheet was heat-treated at a temperature of 250 ° C. for 5 minutes (P
PS sheet-1).

Comparative Example 6 "Torelina" type 3000 manufactured by Toray Co., Ltd.
Was prepared (PPS film-1).

(Evaluation of Examples and Comparative Examples) The fiber sheets of Examples 1 and 2, Reference Example 1 and Comparative Examples 1 to 6,
Tables 1 and 2 show the evaluation results of the laminate, the PPS sheet, and the PPS film.

[0053]

[Table 1]

[0054]

[Table 2]

As shown in Tables 1 and 2, the fiber sheets of the present invention of Examples 1 and 2 do not decrease (but rather improve) the dielectric properties and moisture absorption properties which are the characteristics of PPS. It is excellent in heat resistance and thermal dimensional stability, indicating that the substrate is suitable for high-speed signal processing and high-frequency circuit boards. In addition, there was no problem with the processability of the through hole and the printability of the circuit. In order to improve the dielectric properties of the substrate, which is an object of the present invention, it is important that the dielectric constant and the dielectric loss of the fibrous material at a frequency of 1 MHz are within the ranges of the present invention from Examples 1 and 2 and Comparative Example 2. It turns out that it is.

Further, according to Example 2, the ratio (b / a) of the thickness (a) of the fibrous material impregnated with PPS to the thickness (b) of the layer made of the PPS resin alone is 0.1 to 3.0. The range is preferable in terms of circuit printability, heat shrinkage, and dielectric properties due to the surface roughness of the fiber sheet.

[0057]

In the fiber sheet of Comparative Example 2, the dielectric properties (dielectric loss) of the fibrous material used are poor, and the dielectric properties of the obtained fiber sheet cannot achieve the object of the present invention. Comparative Example 3
Since the fiber sheet is laminated via an adhesive, the adhesive deteriorates heat resistance, dielectric properties, moisture absorption properties and the like. Since the laminate of Comparative Example 4 uses a film instead of a fibrous material, the effect of suppressing the heat shrinkage is smaller than that using a fibrous material. Of the conductive paste or the like is bad. The PPS sheet of Comparative Example 5 has poor heat resistance, and the PPS film of Comparative Example 6 has a large thermal dimensional change rate.

Example 3 An electric circuit was patterned with a silver-containing conductive paint on one side of the fiber sheet of Examples 1 and 2 by silk printing.
Cured at a temperature of 10 ° C. for 10 minutes. Further, the circuit board was subjected to through-hole processing with a conductive paint to form a three-layer laminated circuit board (through-hole diameter: 200 μm). In each of the circuit boards, there was no deformation with respect to the solder at 260 ° C., and there was no displacement of the circuit and the through hole. In addition, high-speed signal processing and high-frequency simulation were performed.
Which circuit board has achieved the object of the present invention.

Comparative Example 7 An electric circuit was provided on one surface of the fiber sheet, the laminate, the PPS sheet, and the PPS film of Comparative Examples 1 to 6 under the conditions of Example 4 to obtain six types of circuit boards. In the case where the fiber sheets of Comparative Examples 1 and 3 were used, the paste permeated into the sheets during the processing of the through holes, and the workability of the through holes was poor. In addition, circuit and through-hole displacement occurred.
In Comparative Example 4, the adhesion of the conductive paste in the through-hole processing was poor in the fluorine-based resin film layer in the center layer of the laminate, and the workability of the through-hole was poor. The one using the PPS sheet of Comparative Example 5 has a problem in solder heat resistance, and the one using the PPS film of Comparative Example 6 has a large heat shrinkage,
The deviation of the circuit and the through hole was large. The one using the fiber sheet of Comparative Example 2 has no problem in solder heat resistance, workability of through-hole processing, circuit, and deviation of through-hole, but achieves the object of the present invention by high-speed signal processing and simulation for high frequency. I didn't.

[0061]

According to the present invention, a material having high-frequency characteristics, moisture-absorbing characteristics, heat resistance, dimensional stability (heat and humidity), etc., is balanced at a high level. It is ideal for high-speed processing and high-frequency compatible circuit boards.

The fiber sheet of the present invention can be used for circuit boards, laminated circuit boards, insulating materials for transformers and motors, covering materials for cables, heat-resistant adhesive tapes, prepreg base materials, heat-resistant labels, speaker base materials, electromagnetic waves, etc. It is most suitable as a shield base material. Further, another material (metal, organic or inorganic sheet) is laminated on at least one surface of the fiber sheet of the present invention, or another resin or coating agent is applied,
It may be molded. Further, the fiber sheet of the present invention may be oxidatively cross-linked by heat, ultraviolet light or the like.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FIB29L 31:34 C08L 27:18 81:02 (56) References JP-A-62-267335 (JP, A) JP-A-61- 54933 (JP, A) JP-A-64-42891 (JP, A) JP-A-63-162731 (JP, A) JP-A-1-139629 (JP, A) JP-A-62-274689 (JP, A) JP-A-63-189440 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 5/04 B29C 70/10 H05K 1/03

Claims (3)

(57) [Claims] 1. A polytetrade having a dielectric constant of 5.0 or less and a dielectric loss of 0.02 or less at a frequency of 1 MHz.
A fibrous sheet fibrous composed mainly of fluoroethylene resin (A) to <br/> polyphenylene sulfide resin composition as a main component (B) is formed by impregnation, 250 ° C.
A fiber sheet having a heat shrinkage of 1.0% or less. 2. The fiber sheet according to claim 1, wherein the fibrous material (A) is a cloth . 3. The fiber cloth according to claim 1 or 2,
Electrical circuit on at least one side of the board
A circuit board characterized by the above-mentioned.